AFTEREFFECTS: THE ASIAN ARENA; BUSH SHIFTS FOCUS TO NUCLEAR SALES BY NORTH KOREA

Tacitly acknowledging that North Korea may not be deterred from producing plutonium for nuclear weapons, President Bush is now trying to marshal international support for preventing the country from exporting nuclear material, American and foreign officials say.

Mr. Bush discussed the new approach on Saturday morning with Australia's prime minister, John Howard, after the two men were given a lengthy briefing at Mr. Bush's ranch by the chief American negotiator with North Korea, James A. Kelly, officials said.

For a decade, the United States' declared policy has been that North Korea would be prevented, by any means necessary, from producing plutonium or highly enriched uranium. President Bill Clinton ordered the Pentagon to draw up plans for a military strike when the North threatened to begin production in 1994, but a nuclear freeze agreement was reached later that year.

Mr. Bush's new focus on blocking the sale of nuclear material to countries or terrorist groups reflects intelligence officials' conclusion that they cannot ascertain whether North Korea was bluffing when it claimed last month that it had already reprocessed enough spent nuclear fuel to make many weapons.

''The president said that the central worry is not what they've got, but where it goes,'' said an official familiar with the talks between Mr. Bush and Mr. Howard. ''He's very pragmatic about it, and the reality is that we probably won't know the extent of what they are producing. So the whole focus is to keep the plutonium from going further.''

Secretary of State Colin L. Powell, in an appearance on the NBC News program ''Meet the Press,'' insisted today that the administration's long-term goal was to force North Korea to dismantle all of its nuclear weapons programs. He vowed that it would get no international aid unless its government changed course.

''Everybody has now made it clear to North Korea that they will not find any assistance coming to them from the region in terms of economic development,'' he said, ''unless they abandon their nuclear weapons programs.''

But in recent interviews, several American officials have said that it was becoming clear that the policy that Mr. Clinton described in 1994 -- when he warned that producing plutonium could result in an American attack to destroy the nuclear facilities at Yongbyon -- was probably not sustainable anymore.

South Korea's new president, Roh Moo Hyun, who will visit Washington for the first time next week, ''has made it clear he won't consider military action of any kind,'' said one senior administration official. ''It's a different atmosphere than in 1994.''

Another official who has discussed the issue with Mr. Bush said his thinking was that the North Koreans ''are looking to get us excited, to make us issue declarations.''

''And his answer to them is,'' the official added, 'You're hungry, and you can't eat plutonium.' ''

Still, Mr. Bush's approach is a major gamble -- one that depends on superb intelligence about North Korea's efforts to sell its weapons. So far, though, the nuclear program has been what one American intelligence official calls ''the black hole of Asia.''

American officials have apparently been unable to find new facilities they believe North Korea is building -- presumably underground -- to produce highly enriched uranium, a technology obtained largely from Pakistan in a trade for missiles.

Unlike North Korea's missiles, which can be seen by satellites as they are loaded into ships and sent to Iran, Syria, Yemen and other nations, weapons-grade nuclear material is easily transportable. Experts say that material would be relatively easy to transport over North Korea's long border with China, part of the reason that Mr. Bush is working to engage the Chinese leadership in confronting North Korea about its nuclear program.

''It's a fantasy to think you can put a hermetic seal around North Korea and keep them from getting a grapefruit-size piece of plutonium out of the country,'' said Ashton B. Carter, a Harvard professor who worked on Korea issues in the Clinton administration, said today. ''To allow North Korea to go nuclear is a major defeat for U.S. security.''

The Bush administration has been deeply divided over how to counter North Korea's efforts to turn its nuclear program into cash, with some of the more hawkish members urging that talks be abandoned. They want the United States and its allies -- including China, if it is willing -- to enforce an embargo that could include the interdiction of North Korean freighters.

Spanish forces intercepted a ship full of missiles headed for Yemen last year, though Mr. Bush decided to let the ship deliver its goods after Yemen's president protested.

Mr. Powell was asked today how the United States would react to the development of a large nuclear arsenal in North Korea, and he answered, ''Their nuclear weapons are not going to purchase them any political standing that will cause us to be frightened or to think that somehow we now have to march to their tune.'' He made no suggestion, however, that the United States would take military action against the main nuclear facilities that Mr. Clinton considered attacking.

But when asked whether the United States would ever allow North Korea to sell or transfer nuclear weapons, Mr. Powell said, ''Absolutely not.''

Secretary of Defense Donald H. Rumsfeld said today that he and other former defense secretaries had been briefed on the military plan in 1994 by the secretary of defense at the time, William J. Perry. But he declined to draw the same ''red line'' for the North Koreans, saying that any decision on military action would have to made by Mr. Bush.

Mr. Bush and Mr. Howard said nothing about North Korea after their meeting on Saturday. Mr. Bush's aides say they hope to continue the low-key approach.

But they are counting on growing aid from China, which was the host of the talks last week. To build support among Chinese leaders there is talk within the administration of letting China convene another meeting. ''We might be willing to go to a second round,'' one senior administration official said. ''The North Koreans have to come prepared to say what they will do, rather than bargain for what they can get.''